Make sure your MidiVerb is plugged in, turned on, and hooked up correctly to your computer through MIDI cables (OUT on your computer goes to IN on the MidiVerb, IN on your computer goes to OUT on your MidiVerb). Make sure the THRU function on your MidiVerb is OFF and PChg is On (access through UTIL button). Make sure you have set up MIDI-OX properly.

If you get "SysEx Error!!!" messages when you are changing system info such as bypass, cascade or input and output volumes, check the AmpX and AmpY settings on the modulators page of your MidiVerb4. Make sure neither is set to 99, then exit and restart PowerMidiVerb4. (There is a small bug in the MidiVerb where you cannot send back this value, and PowerMidiVerb4 sends back whatever value it reads from your MidiVerb4.)

If all else fails, reinitialize your MidiVerb4 by holding down the Prog and D buttons when turning the power one. But make you've backed up your programs first.